Webb finds a lava planet protected by clouds and a molten-rock ocean
The James Webb Space Telescope has found evidence that TOI-561 b, a scorching planet about 280 light-years away, has maintained a thick atmosphere despite the intense heat and radiation expected to drive atmospheric loss over billions of years.
Webb observations indicate that the planet reflects roughly 75% of the starlight reaching it. One possible explanation is a layer of mineral clouds that acts like a giant sunscreen, reducing the amount of stellar energy absorbed by the planet and helping protect its atmosphere.
TOI-561 b may also be continually replenishing its atmosphere. If the planet has a global ocean of molten rock, gases released from that magma could continually replace atmosphere lost to space.
The findings point to a planet unlike many other known lava worlds: its extreme environment may include both a reflective cloud layer and active volcanic replenishment. Astronomers will need further observations to determine how well each mechanism explains the atmosphere.